Homeostasis

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Endothermic

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Hypothalamus

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Exothermic

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Homeostasis

Introduction

Homeostasis is the process by which the body develops physiological and biochemical mechanisms in response to some external factors to maintain its internal physiological environment at a balanced rate. This process is necessary for the continuity of life.

By process of homeostasis, certain factors like blood pressure, blood pH, glucose level, and temperature can be regulated. Homeostasis is governed by control systems in the body such as sensors, control point, communication system, effectors, or target.

Your body has a dynamic equilibrium that maintains balance in the internal environment against the changes in the external environment. The best example of homeostasis is fluctuations in body temperature.

There are two types of feedback mechanisms: (a) Negative feedback and (b) Positive feedback. Both types of feedback work opposite each other. Negative feedback is the main system at work in our body. This feedback system notices any changes in the body and then activates to reverse those changes.

The positive feedback mechanism increases the fluctuations from the set point, i.e. childbirth during delivery.

List Of Factors That Are Regulated In The Body

  • Temperature of the body (37oC)
  • Glucose level of the blood (100mg/ml)
  • Blood pressure (120/80 mm Hg)
  • Blood PH (7.4)

Control Systems In The Body

Sensors - Sensors are also known as receptors. They record information inside or outside of the body.

Control Point  - The control point regulates the information received from the sensors. This system, after having received the information, compares it with the ideal body conditions. If anything goes above or below a set point, then the control system sends the info to the brain via a communication system.

Communication Systems - The endocrine system and the nervous system are the main parts of the communication system. Both play a major role in carrying messages to other parts of the body. These messages move as impulses of hormones, inform the target of the necessary change, and then the target respond accordingly.

Target - A target is an organ. The function of the target is to react according to the messages.

For example, when the outside temperature of the body decreases, the body feels cold and begins to shiver. In shivering, muscles work rapidly and increase the temperature of the body.

screenshot_01Feedback Systems

Most control systems of the body act by negative feedback. This process detects fluctuations in the body system and then reverses them. It includes three parts: a receptor, an integrator, and effectors.

Steps involved in the negative feedback mechanism:

  • When the body temperature increases, it sends a message in the form of impulses to sensory receptors.
  • These sensory receptors send impulses to the integrator.
  • The integrator will send messages to effectors.
  • Finally, effectors respond and blood vessels near the skin dilate.
  • Once the temperature returns to normal, it will limit the response of effectors.

screenshot_02

Positive feedback loops

Positive feedback exists in a diseased condition, and is therefore rare in the human body. In this system, the control center gathers information from the sensors and increases in the change from the set point.

During delivery, a baby’s head pushes against the uterine opening. When uterine muscle contraction increases, they send impulses to the hypothalamus, which releases oxytocin to increase the strength of the uterine muscles to help move the baby's head out. This process of contraction continues until the baby is born.

Summary

Homeostasis is the body's balancing act to maintain dynamic equilibrium, which is the balance between what the body needs the internal environment to be and what the external environment actually is. When the body's sensors recognize that something is wrong, such as the temperature being too low, the control point sends the information through the communication system, which is mostly the endocrine and nervous systems. Then, the target receives the appropriate message and responds. With the example above, the target would be muscles, and the message they would receive would be to shiver. When the body shivers, it burns fat rapidly to produce body heat, which raises the core temperature.

There are two types of feedback, which work opposite each other. The negative feedback system works to reverse a recognized change in conditions, and works through receptors, integrators, and effectors. Positive feedback works to continue a change, but is far less common than negative feedback.

 

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